class_docstr: Deep structured semantic model.
  
  Examples:
      >>> model = DSSM()
      >>> model.params['mlp_num_layers'] = 3
      >>> model.params['mlp_num_units'] = 300
      >>> model.params['mlp_num_fan_out'] = 128
      >>> model.params['mlp_activation_func'] = 'relu'
      >>> model.guess_and_fill_missing_params(verbose=0)
      >>> model.build()
docstr: :return: Default preprocessor.
docstr_tok: [":","return",":","Default","preprocessor","."]
code: def get_default_preprocessor(cls):
      """:return: Default preprocessor."""
      return preprocessors.DSSMPreprocessor()
  
file_path: MatchZoo/matchzoo/models/dssm.py
imports: from keras.models import Model
  from keras.layers import Input, Dot
  from matchzoo.engine.param_table import ParamTable
  from matchzoo.engine.base_model import BaseModel
  from matchzoo import preprocessors
label_desc: Use image node_id 3 for calling the DSSM obj's underlying member method code with example usage: obj.get_default_preprocessor(cls) and returns: preprocessors